This invention relates to improvements in a winding method and winding device for winding a wire around the stator core of an electric motor or a generator.
As conventional winding methods applied to an inner rotor type stator, a direct winding method in which a wire is directly wound onto teeth, and an inserter winding method in which a pre-wound wire is inserted into a slot are known. The following methods described in (a) and (b) are direct winding methods.
(a) A direct winding method in which a wire is wound onto a core by inserting a nozzle which supplies the wire into the interior of each slot.
(b) A direct winding method in which a wire is wound onto a core by moving the nozzle which supplies the wire on the outside of each slot.
The following method described in (c) is an inserter winding method.
(c) An inserter winding method in which a wire is wound in advance onto a rod-shaped member disposed along the inside of teeth, whereupon the wire is inserted into a slot.
Tokkai 2000-270524, published by the Japanese Patent Office in 2000, and Tokkai 2001-103716, published by the Japanese Patent Office in 2001, disclose as a winding device for performing a direct winding method, a winding device comprising a hooker which leads a point on a wire supplied from a nozzle into a slot.
Tokkai 2000-245120, published by the Japanese Patent Office in 2000, discloses an inserter winding method.
However, although the direct winding methods (a) and (b) are applied to concentrated winding in which wires are wound in concentration onto each tooth, these methods cannot be applied to distributed winding in which wires are wound over a plurality of teeth. If an attempt is made to perform distributed winding using the direct winding methods in (a) and (b), the wire of the initially wound phase over the slot causes an obstruction such that the wire to be wound in the following phases cannot be wound. Even if the wires are inserted into the slots by manual labor, a gap appears between the core and the wire, with the result that the wire space factor (density) in respect of the core cannot be increased.
When distributed winding is performed in the inserter winding method in (c), the space factor of a wire is increased by inserting the wire into the back of a slot. However, the coil end portion of the winding increases in length, leading to an increase in the size of the coil and the necessity for a procedure to shape the coil end portion. Moreover, even if the coil end portion does not affect the torque generated by the motor, when the coil end portion increases in length, the amount of heat generation increases due to copper loss.
An object of this invention is to provide a winding method and winding device in which the wire space factor of the coil portion is raised and the coil end portion is shortened.
In order to achieve above object, this invention provides a winding method for forming coils onto a substantially cylindrical core being provided with a substantially cylindrical yoke, a plurality of teeth which protrude from the yoke in a radial direction and slots formed between adjacent teeth, the winding method comprising the steps of: providing a nozzle for letting out a wire; providing a guide for guiding the wire into a slot; moving the nozzle three-dimensionally relative to the core so as to form a coil; moving the guide relative to the core in the radial direction of the core; and inserting the wire into the slot by the movement of the guide relative to the core.
The winding method may further comprise the steps of: forming a first coil such that two or more teeth are disposed inside the first coil; spacing a coil end portion of the first coil from an axial end face of the teeth; and when a second coil is formed such that at least one common tooth is included within the first coil and within the second coil, inserting a side portion of the second coil, into a space defined by the teeth and the coil end portion of the first coil such that the side portion of the second coil is substantially in contact with a bottom of a slot.
Further, this invention provides a winding device for forming coils onto a substantially cylindrical core being provided with a substantially cylindrical yoke, a plurality of teeth which protrude from the yoke in a radial direction and slots formed between adjacent teeth. The winding device comprises a nozzle for letting out a wire; a nozzle moving mechanism for moving the nozzle three-dimensionally relative to the core in order to form a coil, wherein the wire is wound around two or more teeth by the three-dimensional movement of the nozzle; a guide for guiding the wire into a slot; and a guide moving mechanism for moving the guide relative to the core in the radial direction of the core, wherein the wire is inserted into the slot by the movement of the guide relative to the core.